Engine room heat exhausting structure

ABSTRACT

An engine room heat exhausting structure configured to discharge heat from an engine room, is provided, which includes an engine room accommodating an engine with cylinders lined up in a front-and-rear direction of a vehicle, a wheelhouse provided outside the engine room in a vehicle width direction, an exhaust emission control device disposed between the engine and the wheelhouse, a wheelhouse liner configured to protect an inner wall of the wheelhouse, a discharging part provided rearward of the exhaust emission control device and configured to discharge into the wheelhouse a part of air cooled the exhaust emission control device, and a guiding part provided to the wheelhouse liner and configured to guide the air discharged into the wheel house to underneath the vehicle in a rear part of the wheelhouse.

TECHNICAL FIELD

The present disclosure relates to an engine room heat exhaustingstructure which discharges heat from an engine room of a vehicle.

BACKGROUND OF THE DISCLOSURE

Conventionally, an engine room where an engine which generates heat isaccommodated is provided in a front part of a vehicle. The engine roomis defined by a dash panel, front inside panels, and an engine hood. Thedash panel defines a rear part of the engine room, the front insidepanels define both sides in the vehicle width direction, and the enginehood defines an upper part. The heat generated inside the engine room isexhausted forward of a front window screen, into wheelhouses, anddownward of the engine room, while utilizing air for cooling which isintroduced into the engine room by a traveling wind (i.e., wind causedby the vehicle traveling).

Meanwhile, the engine may be covered by an engine cover in order tomainly improve sound insulation. Moreover, in order to protect theengine, etc. from a collision with a pebble while the vehicle travelsand rectify air which passes through a space underneath the vehicle, anundercover may be attached for covering the engine room from below.

In such cases, since it becomes difficult to exhaust the heat from theengine room because of the engine cover and the undercover, structuresfor stimulating the heat discharge from the engine room have beenexamined. For example, like JP6091782B2, there is a known technologywhich defines the engine room by an engine encapsulation structure whichcovers the engine. The cooling air is introduced into the engineencapsulation structure from the front and flows rearward. Thus, thestructure stimulates the heat discharge and improves the soundinsulation, the thermal insulation, and the pedestrian protection whenthe vehicle collides with a pedestrian.

However, when a driving force transmission mechanism, such as thetransmission, is disposed rearward of a lower part of the engine, sincethe cooling air which cooled the engine and became hot reaches theperiphery of the driving force transmission mechanism, the driving forcetransmission mechanism may be overheated. Therefore, it is consideredthat the hot cooling air is discharged into the wheelhouses.

While the vehicle is traveling, air flows into the wheelhouses from thefront, and then flows rearward to exit from the wheelhouses. Sinceturbulence occurs at this time to increase air resistance, it is knownthat air flowing into the wheelhouses from underneath of the vehicle isreduced by a deflector and air is drawn into the wheelhouses from theside of the vehicle to suppress the increase in the air resistance, forexample, like JP2020-001425A.

However, when the cooling air is discharged into the wheelhouses, sincethe cooling air collides with the air flowing inside the wheelhouses todisturb the flow, air resistance increases. In addition, the cooling airmay become difficult to be discharged into the wheelhouses, andtherefore, the heat discharge from the engine room cannot be fullyachieved.

SUMMARY OF THE DISCLOSURE

The present disclosure is made in view of addressing the situationsdescribed above, and one purpose thereof is to provide an engine roomheat exhausting structure capable of suppressing an increase in airresistance when a vehicle travels, while stimulating the heat dischargefrom the engine room.

According to one aspect of the present disclosure, an engine room heatexhausting structure configured to discharge heat from an engine room,is provided. The structure includes an engine room accommodating anengine with cylinders lined up in a front-and-rear direction of avehicle, a wheelhouse provided outside the engine room in a vehiclewidth direction, an exhaust emission control device disposed between theengine and the wheelhouse, a wheelhouse liner configured to protect aninner wall of the wheelhouse, a discharging part provided rearward ofthe exhaust emission control device and configured to discharge into thewheelhouse a portion of air cooled the exhaust emission control device,and a guiding part provided to the wheelhouse liner and configured toguide the air discharged into the wheelhouse to underneath the vehiclein a rear part of the wheelhouse.

According to this structure, the exhaust emission control device and anexhaust passage connected thereto/therefrom, which became especiallyhigh in temperature because hot exhaust gas after combustion passesthrough, are cooled from outside by cooling air introduced into theengine room from the front when the vehicle travels. The portion of thecooling air which became high in temperature after cooling the exhaustemission control device is discharged into the wheelhouse from thedischarging part provided to the splash shield at a location rearward ofthe exhaust emission control device. The cooling air discharged into thewheelhouse is smoothly guided underneath the vehicle at the rear part ofthe wheelhouse while colliding with the air flowing inside thewheelhouse. Thus, the heat discharge from the engine room can bestimulated and an increase in air resistance when the vehicle travelscan be suppressed.

The guiding part may have a curved surface part in a rearward lower endpart of the wheelhouse liner, the curved surface part having such an arcshape in cross section that the curved surface part becomes lower towardthe rear. According to this structure, since the cooling air dischargedinto the wheelhouse when the vehicle travels is smoothly guidedunderneath the vehicle by the curved surface part, the increase in theair resistance can be suppressed.

The guiding part may have an inclined part extending rearward from thecurved surface part so that the inclined part becomes lower toward therear, and the curved surface part and the inclined part may be formedintegrally with the wheelhouse liner. According to this structure, sincethe cooling air discharged into the wheelhouse when the vehicle travelsis smoothly guided underneath the vehicle by the curved surface part andthe inclined part, the increase in air resistance can be suppressed.

The engine room heat exhausting structure may further include a heatshielding cover covering an upper surface part, side surface parts, anda rear surface part of the engine inside the engine room, and anundercover covering the engine room from below. The discharging part maybe provided to a part of a splash shield configured to intercept waterentering the engine room from the wheelhouse, between a lower end of theside surface part of the heat shielding cover and the undercover.According to this structure, the part of the cooling air introduced tothe inside of the heat shielding cover from forward is discharged intothe wheelhouse, from the discharging part provided to the splash shieldat a location between the lower end of the side surface part of the heatshielding cover and the undercover. Therefore, the heat discharge fromthe engine room can be stimulated. Further, since the cooling airdischarged into the wheelhouse is smoothly guided underneath the vehicleby the guiding part, the increase in the air resistance can besuppressed.

The air may be introduced into the engine room from the front through afront opening of the vehicle by traveling wind or a blower fan.

The wheelhouse is one of a pair of left and right wheelhousesaccommodating front wheels and may be provided outside of the engineroom in the vehicle width direction. The wheelhouse liner may be one ofa pair of wheelhouse liners respectively configured to protect an innerwall of each of the wheelhouses and improve sound insulation, and may beattached to each of the wheelhouses. A respective splash shield may befixed to a front side frame or to each of the wheelhouse liners. Thedischarging part may be formed by notching a part that is a rear part ofone of the splash shields and rearward and downward of the exhaustemission control device, or by making a hole in the part.

The engine room heat exhausting structure may further include a heatshielding cover covering an upper surface part and side surface parts ofthe engine. The air introduced into the heat shielding cover from theengine room may flow rearward of a lower part of the engine, below theheat shielding cover and along an upper part or a side part of theengine. The air contacted the exhaust emission control device may bedischarged into a rear part of the wheelhouse through the dischargingpart provided at an intermediate location of a channel where the airflows rearward of the lower part of the engine.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a view schematically illustrating a front part of a vehicle.

FIG. 2 is a side view illustrating a substantial part of a wheelhouse ina state where a wheelhouse liner is attached.

FIG. 3 is a side view illustrating a spatial relationship of awheelhouse and an exhaust emission control device.

FIG. 4 is a cross-sectional view taken along a line IV-IV in FIG. 3 .

FIG. 5 is a view schematically illustrating a discharging part of asplash shield and a guiding part of the wheelhouse liner.

FIG. 6 is a side view of an engine mount.

FIG. 7 is a cross-sectional view illustrating a part of the wheelhouseliner, taken along a line VII-VII in FIG. 4 .

DETAILED DESCRIPTION OF THE DISCLOSURE

Hereinafter, one embodiment for implementing the present disclosure isdescribed with reference to the accompanying drawings. The followingdesirable embodiment is merely illustration, and it is not intended tolimit the present disclosure and applications thereof.

As illustrated in FIG. 1 , an engine room 1 is provided in a front partof a vehicle V. Below, an arrow F, an arrow L, and an arrow U in thedrawings indicate front, left, and up of the vehicle, respectively.Inside the engine room 1, a multi-cylinder engine 3 in which a pluralityof cylinders are lined up in a front-and-rear direction (a so-called“longitudinal engine”) is accommodated between a pair of front sideframes 2 extending in the front-and-rear direction of the vehicle V. Theengine 3 is covered by an engine cover (hereinafter, referred to as a“heat shielding cover 4”) at an upper surface part, a rear surface part,and left and right side surface parts, and the part covering the uppersurface part is openable and closable.

The engine room 1 is defined in a vehicle width direction by frontinside panels (outside the figure) coupled to the pair of front sideframes 2, and is defined in the front-and-rear direction by a dash panel(outside the figure) located between the engine room 1 and a cabinrearward of the engine room 1. A driving force transmission mechanism 5having a transmission is disposed rearward of a lower part of the engine3, and in order to transmit a driving force to rear wheels, the drivingforce transmission mechanism 5 extends rearward along a floor tunnelprovided in a floor panel extending rearward from the dash panel(outside the figure). An upper part of the engine room 1 is covered byan engine hood (outside the figure) which is openable and closable.

The heat shielding cover 4 is made of, for example, a synthetic resinmaterial, having a heat insulation function, and it divides an internalspace of the engine room 1 into a high-temperature area inside the heatshielding cover 4 and a low-temperature area outside the heat shieldingcover 4. In addition, it protects components (e.g., a battery) disposedoutside the heat shielding cover 4 from heat of the engine 3. Moreover,the heat shielding cover 4 has a sound insulating function which coversthe engine 3 and improves sound insulation, and a protective functionwhich reduces an impact on a pedestrian between the pedestrian and theengine 3 when the vehicle collides with the pedestrian.

A radiator and a blower fan (both outside the figure) are disposedforward of the engine 3, and cooling air indicated by arrows isintroduced into the engine room 1 normally from the front through afront opening of the vehicle V by a traveling wind (i.e., wind caused bythe vehicle traveling) or the blower fan. The cooling air introducedinside the heat shielding cover 4 among the cooling air introduced intothe engine room 1 flows toward the driving force transmission mechanism5 rearward of the lower part of the engine 3, through between the engine3 and the heat shielding cover 4. The cooling air which is notintroduced inside the heat shielding cover 4 cools the components (e.g.,the battery) outside the heat shielding cover 4.

A pair of left and right wheelhouses 6 which accommodate front wheelsare provided outside of the engine room 1 in the vehicle widthdirection. Between the engine 3 and one of the wheelhouses 6, an exhaustemission control device 7 for purifying exhaust gas of the engine 3 isdisposed. For example, an intake system which supplies air forcombustion to the engine 3 is disposed on the left side of the engine 3,an exhaust system is disposed on the right side of the engine 3, and theexhaust emission control device 7 is disposed between the wheelhouse 6of the right front wheel and the engine 3. Below, the wheelhouse 6 ofthe right front wheel and the exhaust emission control device 7 aremainly described, but the left and right wheelhouses 6 are largelysymmetrical and most of the redundant description is omitted.

As illustrated in FIGS. 1 to 5 , a wheelhouse liner 11 for protecting aninner wall of the wheelhouse 6 from a collision with a pebble, etc. andimproving sound insulation is attached to the wheelhouse 6. Moreover, asplash shield 12 for intercepting water, a pebble, etc. which enter theengine room 1 from the wheelhouse 6 when the front wheels of thetraveling vehicle V rotate is fixed to the front side frame 2, etc. withbolts, push rivets, etc. The wheelhouse liner 11 and the splash shield12 are made of, for example, a synthetic resin material, in order toreduce the weight while reducing the noise caused by the collision withthe pebble, etc.

In a lower part of the wheelhouse 6, a lower arm 14 rotatably supportedby a sub-frame 8 extending in the front-and-rear direction below thefront side frame 2 and a tie rod 15 which constitutes a steeringmechanism extend from the center side in the vehicle width direction. Adamper 16 with a coil spring is fixed at an upper part, for example, toa given location of a front inside panel 1 a. A lower part of the damper16 is attached to the lower arm 14, and they constitute a suspensionmechanism. An engine mount 18 for fixing the engine 3 is fixed to thesub-frame 8 and the front side frame 2.

As illustrated in FIG. 6 , the engine mount 18 includes a cylindricalbody part 18 a, an upper fixing part 18 b for fixing the body part 18 ato the front side frame 2, and a front lower part fixing part 18 c and arear lower part fixing part 18 d which are formed so that they spread inthe front-and-rear direction as it goes downward from the upper fixingpart 18 b in order to fix the body part 18 a to the sub-frame 8. Theengine 3 is fixed to the body part 18 a through a bracket 18 e. Thecylindrical body part 18 a inclines so that an upper surface of the bodypart 18 a to which the bracket 18 e is fixed faces upward and inward inthe vehicle width direction (see FIG. 4 ). The rear lower part fixingpart 18 d inclines downward and outward in the vehicle width directionso that it follows the inclination of the body part 18 a.

As illustrated in FIG. 5 , the wheelhouse liner 11 is notched in acenter part in the front-and-rear-direction from an upper part to alower end of an inward part in the vehicle width direction, for thesuspension mechanism, the steering mechanism, etc. The notched middlepart of the wheelhouse liner 11 is coupled by the splash shield 12, andan upper part above the middle part is coupled by a connecting member13.

As illustrated in FIGS. 2 to 4 , above the splash shield 12, waterentering the engine room 1 is intercepted because the wheelhouse 6 andthe engine room 1 are divided by the front side frame 2 and the frontinside panel 1 a which extends upwardly from the front side frame 2. Theexhaust emission control device 7 between the wheelhouse 6 and theengine 3 is disposed above the splash shield 12.

The exhaust emission control device 7 purifies exhaust gas of the engine3 introduced from a front upper part thereof and discharges the purifiedexhaust gas to an exhaust passage 7 a extending rearward from a rearlower part thereof. A lower end of a side surface part of the heatshielding cover 4 covering the engine 3 extends to a position so as tocover the lower end of the exhaust emission control device 7 and isfixed to the front side frame 2. A lower part of the engine room 1 iscovered by an undercover 19 fixed to the sub-frame 8 so that it preventsthe collision of the pebble to the engine 3 and rectifies air passingthrough a space underneath the vehicle V, while traveling.

As illustrated in FIG. 5 , the splash shield 12 is provided with adischarging part 20 for communicating the engine room 1 with a rear partof the inside of the wheelhouse 6 via a hatched area E. This hatchedarea E is an opening area between the splash shield 12 and the rearlower part fixing part 18 d of the engine mount 18, and is an areaconventionally covered by the splash shield 12 for preventing waterentering the engine room 1. The discharge of the cooling air from thedischarging part 20 stimulates the heat discharge and suppresses thewater entering the engine room 1 through the discharging part 20. Inthis embodiment, the discharging port 20 may be provided to only thewheelhouse 6 of the right front wheel and not the wheelhouse 6 of theleft front wheel, because the exhaust emission control device 7 isprovided to the right side of the vehicle.

This discharging part 20 is formed by notching a part which is a rearpart of the splash shield 12 and rearward and downward of the exhaustemission control device 7, but it may be formed by making a hole in thispart of the splash shield 12. Moreover, the discharging part 20 isprovided rearward of a front end of the body part 18 a of the enginemount 18. In addition, the discharging part 20 is provided in a partbetween the lower end of the side surface part of the heat shieldingcover 4 and the undercover 19.

As illustrated in FIGS. 4, 5 and 7 , a rearward lower end part of thewheelhouse liner 11 is provided with a guiding part 11 b for guidingcooling air discharged into the wheelhouse 6 to underneath the vehicleV, in a rear part of the wheelhouse 6. A deflector 11 a is attached to aforward lower end part of the wheelhouse liner 11, for reducing the airresistance by traveling wind (i.e., wind caused by the vehicletraveling) caught in the wheelhouse 6.

The guiding part 11 b continues smoothly from the rearward lower endpart of the wheelhouse liner 11, and has a curved surface part 11 chaving an arc shape in cross section so that it becomes lower as it goesrearward, and an inclined part 11 d extending rearward from the curvedsurface part 11 c so that it becomes lower as it goes rearward. Theguiding part 11 b including the curved surface part 11 c and theinclined part 11 d is formed integrally with the wheelhouse liner 11.The cooling air discharged into the wheelhouse 6 flows along the guidingpart 11 b, and is smoothly led to underneath the vehicle V in the rearpart of the wheelhouse 6.

For example, along the shape of the lower part of the vehicle V, theguiding part 11 b has two curved surface parts 11 c disposed in thevehicle width direction, and two inclined parts 11 d corresponding tothe two curved surface parts 11 c. The two curved surface parts 11 c andthe two inclined parts 11 d have the same function, and they lead thecooling air rearward at a location inward of a side sill garnish 21 inthe vehicle width direction, which protects a side sill rearward of thewheelhouse 6.

Operation and effects of the engine room heat exhausting structure ofthis embodiment are described. When the vehicle V travels, the coolingair is introduced into the engine room 1 from the front due to thetraveling wind. The cooling air is divided into what is dischargedforward of a front window screen, what is discharged into the wheelhouse6, and what is discharged downwardly from the rear part of the vehiclethrough the floor tunnel.

The cooling air introduced into the heat shielding cover 4 from theengine room 1 flows rearward of the lower part of the engine 3 along theupper part or the side part of the engine 3. As illustrated by thearrows in FIGS. 1, 3 and 4 , among them, the cooling air which flowsalong the side part of the engine 3 on the exhaust system side flowsnear the exhaust emission control device 7 and cools the exhaustemission control device 7.

A portion of the cooling air which became high in temperature aftercooling the exhaust emission control device 7 flows rearward of thelower part of the engine 3, and on the way, it flows from the inside ofthe heat shielding cover 4 into the engine room 1. Then, the cooling airis discharged to the rear part of the wheelhouse 6 through thedischarging part 20 provided at the intermediate location of the flow ofthe cooling air rearward of the lower part of the engine 3. The coolingair discharged into the wheelhouse 6 is guided rearward of thewheelhouse 6 by the guiding part 11 b, and is smoothly guided underneaththe vehicle V at the rear part of the wheelhouse 6. Therefore, the heatdischarge inside the engine room 1 can be stimulated, and the increasein air resistance which is caused by the cooling air colliding with theair flowing inside the wheelhouse 6 to disturb the flow when the vehicletravels can be suppressed.

The guiding part 11 b has the curved surface part 11 c having the arcshape in cross section in the rearward lower end part of the wheelhouseliner 11 so that it becomes lower as it goes rearward. Thus, since thecooling air discharged into the wheelhouse 6 is guided rearward of thewheelhouse 6 by the curved surface part 11 c while the vehicle V istraveling and is smoothly guided underneath the vehicle V, the increasein air resistance when the vehicle travels can be suppressed.

Moreover, the guiding part 11 b has the inclined part 11 d extendingrearward of the vehicle V from the curved surface part 11 c so that itbecomes lower as it goes rearward, and the guiding part 11 b includingthe curved surface part 11 c and the inclined part 11 d is formedintegrally with the wheelhouse liner 11. Therefore, since the coolingair discharged into the wheelhouse 6 is guided rearward of thewheelhouse 6 by the curved surface part 11 c and the inclined part 11 dand is smoothly guided underneath the vehicle V while the vehicle V istraveling, the increase in the air resistance when the vehicle travelscan be suppressed.

Moreover, the cooling air which came out from the heat shielding cover 4into the engine room 1 flows rearward of the lower part of the engine 3along the side part of the engine 3, without being discharged downwardlyfrom the vehicle V because of the undercover 19. The portion of thecooling air is discharged into the wheelhouse 6 on the way of the flowroute, from the discharging part 20 which is provided in the part of thesplash shield 12 between the lower end of the side surface part of theheat shielding cover 4 and the undercover. Therefore, the heat dischargefrom the engine room 1 can be stimulated.

The above description concerns a configuration in which the exhaustemission control device 7 is provided between the engine 3 and thewheelhouse 6 of the right front wheel. However, the exhaust emissioncontrol device 7 may be disposed between the wheelhouse 6 for the leftfront wheel and the engine 3, and, for example, when the engine 3 is aV-engine, it may be disposed at both the left and the right. Alsosimilarly in these cases, by providing the discharging part 20 of thesplash shield 12 and the guiding part 11 b of the wheelhouse liner 11 tothe wheelhouse(s) 6 corresponding to the exhaust emission controldevice(s) 7, the heat discharge from the engine room 1 can bestimulated, and the increase in air resistance when the vehicle travelscan be suppressed. Note that various modifications of the aboveembodiment are possible by the person skilled in the art withoutdeparting from the spirit of the present disclosure, and the presentdisclosure also encompasses these modifications.

It should be understood that the embodiments herein are illustrative andnot restrictive, since the scope of the invention is defined by theappended claims rather than by the description preceding them, and allchanges that fall within metes and bounds of the claims, or equivalenceof such metes and bounds thereof, are therefore intended to be embracedby the claims.

DESCRIPTION OF REFERENCE CHARACTERS

-   -   1: Engine Room    -   2: Front Side Frame    -   3: Engine    -   4: Heat Shielding Cover    -   5: Driving Force Transmission Mechanism    -   6: Wheelhouse    -   7: Exhaust Emission Control Device    -   8: Sub-frame    -   11: Wheelhouse Liner    -   11 a: Deflector    -   11 b: Guiding Part    -   11 c: Curved Surface Part    -   11 d: Inclined Part    -   12: Splash Shield    -   14: Lower Arm    -   15: Tie Rod    -   16: Damper    -   18: Engine Mount    -   18 c: Front Lower Part Fixing Part    -   18 d: Rear Lower Part Fixing Part    -   19: Undercover    -   20: Discharging Part    -   21: Side Sill Garnish

What is claimed is:
 1. An engine room heat exhausting structureconfigured to discharge heat from an engine room, comprising: an engineroom accommodating an engine with cylinders lined up in a front-and-reardirection of a vehicle; a wheelhouse provided outside the engine room ina vehicle width direction; an exhaust gas purification device disposedbetween the engine and the wheelhouse; a wheelhouse liner configured toprotect an inner wall of the wheelhouse; a discharging part providedrearward of the exhaust gas purification device and configured todischarge into the wheelhouse a portion of air that cooled the exhaustgas purification device; and a guiding part provided to the wheelhouseliner and configured to guide the air discharged into the wheelhouse tounderneath the vehicle in a rear part of the wheelhouse.
 2. The engineroom heat exhausting structure of claim 1, wherein the guiding part hasa curved surface part in a rearward lower end part of the wheelhouseliner, the curved surface part having such an arc shape in cross sectionthat the curved surface part becomes lower toward the rear.
 3. Theengine room heat exhausting structure of claim 2, wherein the guidingpart has an inclined part extending rearward from the curved surfacepart so that the inclined part becomes lower toward the rear, and thecurved surface part and the inclined part are formed integrally with thewheelhouse liner.
 4. The engine room heat exhausting structure of claim3, further comprising: a heat shielding cover covering an upper surfacepart, side surface parts, and a rear surface part of the engine insidethe engine room; and an undercover covering the engine room from below,wherein the discharging part is provided to a part of a splash shieldconfigured to intercept water entering the engine room from thewheelhouse, between a lower end of the side surface part of the heatshielding cover and the undercover.
 5. The engine room heat exhaustingstructure of claim 1, further comprising: a heat shielding covercovering an upper surface part, side surface parts, and a rear surfacepart of the engine inside the engine room; and an undercover coveringthe engine room from below, wherein the discharging part is provided toa part of a splash shield configured to intercept water entering theengine room from the wheelhouse, between a lower end of the side surfacepart of the heat shielding cover and the undercover.
 6. The engine roomheat exhausting structure of claim 1, wherein the air is introduced intothe engine room from the front through a front opening of the vehicle bytraveling wind or a blower fan.
 7. The engine room heat exhaustingstructure of claim 5, wherein the wheelhouse is one of a pair of leftand right wheelhouses accommodating front wheels and provided outside ofthe engine room in the vehicle width direction, wherein the wheelhouseliner is one of a pair of wheelhouse liners respectively configured toprotect the inner wall of each of the wheelhouses and improve soundinsulation, and are attached to each of the wheelhouses, wherein arespective splash shield is fixed to a front side frame or to each ofthe wheelhouse liners, and wherein the discharging part is formed bynotching a part that is a rear part of one of the splash shields andrearward and downward of the exhaust gas purification device, or bymaking a hole in the part.
 8. The engine room heat exhausting structureof claim 7, further comprising a heat shielding cover covering an uppersurface part and side surface parts of the engine, wherein the airintroduced into the heat shielding cover from the engine room flowsrearward of a lower part of the engine, below the heat shielding coverand along an upper part or a side part of the engine, and wherein theair contacted the exhaust gas purification device is discharged into therear part of the wheelhouse through the discharging part provided at anintermediate location of a channel where the air flows rearward of thelower part of the engine.
 9. The engine room heat exhausting structureof claim 1, further comprising a heat shielding cover covering an uppersurface part and side surface parts of the engine, wherein the airintroduced into the heat shielding cover from the engine room flowsrearward of a lower part of the engine, below the heat shielding coverand along an upper part or a side part of the engine, and wherein theair contacted the exhaust gas purification device is discharged into therear part of the wheelhouse through the discharging part provided at anintermediate location of a channel where the air flows rearward of thelower part of the engine.